Solar Plastic Recycling

Sun Factory Project — Complete Educator's Guide

This guide is the outcome of the Sun Factory Lisbon 2026 Residency, held at FabLab Benfica, Lisbon (29 June – 11 August 2026).

solar energy plastic recycling FabLab open-source circular economy educator guide workshop

Before building, understand why and how — the vision, principles, and science behind solar plastic recycling.

1.1 What is Sun Factory Project?

Sun Factory Project is an international contributive initiative that empowers local communities through solar energy for artisanal manufacturing. Based in Geneva and supported by the Antenna Foundation, the project develops simple, open-source machines to capture the heat of the Sun for multiple applications: cooking, puffed cereals, recycling plastic, and all solar thermal processes — alongside photovoltaic solutions. All documentation is shared under CC BY-SA 4.0 and hardware designs under CERN-OHL-S-2.0 — free to copy, modify, and redistribute — as long as you credit the authors and keep it open.

The Big Idea: Sunlight + Circular Economy

• Renewable energy: Instead of burning fuel, mirrors concentrate sunlight to reach high temperatures (up to 300°C)
• Circular economy: Instead of throwing plastic away, we melt it and give it a new life as a useful object
• Community independence: The instructions are free — teaching communities to build, repair and use the technology themselves

1.2 Core Principles

Sun Factory Project is built on emancipation and economic independence — offering low-tech solutions for self-reliance rather than dependency on capitalist systems.

Why GAFAM-Free?

Being fully open source and GAFAM-free is central to our identity. We oppose data exploitation and tech dependency, using only privacy-respecting tools: Mastodon, Pixelfed, Nextcloud, and GitLab. We also build our own tools when needed, with all data hosted in Switzerland by Infomaniak — no personal data collected or used, ever, protected by Swiss privacy law. This means smaller audiences but truly free knowledge without surveillance or paywalls.

The Four Pillars

From Knowledge to Action

These principles translate into concrete outcomes: communities can replicate the technology anywhere in the world, improve designs and share modifications, translate documentation into local languages, and connect with the global Sun Factory network. The instructions are free — the goal is independence.

1.3 Naphtha and Plastics

From Petroleum to Plastic

All conventional plastics originate from petroleum — a finite fossil resource. The process begins with naphtha (from Greek "naphtha" meaning flammable), a hydrocarbon mixture obtained during oil refining. Naphtha is "cracked" at high temperatures to produce monomers like ethylene and propylene, which are then polymerized into the plastics we use daily.

The renewable energy paradox: Even the transition to green energy requires enormous amounts of energy to manufacture solar panels, wind turbines, and batteries. This energy demand keeps refineries running — and naphtha is an unavoidable byproduct of petroleum refining. As long as we refine oil for any purpose, we produce naphtha. And naphtha becomes plastic. The ecological transition, paradoxically, guarantees continued plastic production for decades to come.

Despite growing awareness, global plastic production continues to rise. According to industry projections, plastic pollution is not expected to decrease — making local recycling solutions increasingly vital.

Plastic Types Used in Sun Factory

Not all plastics are equal. Sun Factory Project works primarily with thermoplastics — plastics that can be melted and reshaped multiple times without losing structural integrity:

1.4 The Solar Plastic Recycling Process

Solar Plastic Injection is a Swiss initiative born from maker innovation in Geneva. In 2020, Marco Bernardo — combining African solar expertise with Swiss precision engineering — partnered with Yann Camponovo of PlastOK to create a breakthrough: melting plastic using only sunlight. On July 20, 2020, the complete process was published on Instructables — making it freely replicable worldwide.

The process uses four machines working together — all designs are open source under CC BY-SA 4.0: free to copy, adapt, and share, as long as you credit the authors and keep it open.

1.5 Learning Goals & Audience

Sun Factory Project is designed for everyone — from curious children to professional makers. The technology is intentionally accessible: simple enough for educational workshops, yet powerful enough to generate income for independent artisans.

Who This is For

From Learning to Earning

The pedagogic approach works on two levels: for children, it's about discovery — understanding solar energy, the plastic challenge, and the power of open technology. For adults, it's also about economic independence — the same machines used in workshops can become tools for livelihood, transforming waste into sellable products with minimal investment.

What Participants Should Take Away

Step-by-step guides to build each machine — all designs are open source and replicable in any FabLab.

2.1 Solar Concentrator

"The goal is to explain how version 3 of the solar concentrator was designed and built so that anyone can replicate it in a FabLab or digital fabrication lab."

Bill of Materials (BOM)

Tools Required

• CNC Router (or jigsaw for manual cutting)
• Drill with 6.5mm bit
• Screwdriver
• Safety glasses

Assembly Steps

2.2 Injection Cartridge

To facilitate the injection of recycled plastic using solar thermal energy, Plastok prototyped the metal cartridge injection process. Building upon Plastok's work, the cartridges developed by volks.eco are essential for portable injections and are worldwide DIY.

Bill of Materials

Tools Required

• Metal file
• Metal saw
• Hammer for securing components
• Sandpaper for polishing surfaces
• Drill + 3mm metal drill bit

Assembly Steps

2.3 Manual Injector

"My goal was to create a new design that maintains the open-source, replicable nature of the project while staying intuitive to use, robust in operation, and easy to manufacture in a FabLab environment."

Bill of Materials

Assembly Steps

2.4 Molds

"A plastic injection mold is the component responsible for shaping the object manufactured through the injection molding process."

Design Guidelines

• Material: Transparent resin (enables observation of plastic flow)
• Connection: Compatible with 1/2" cartridge thread
• Draft angles: Include for easy part ejection
• Wall thickness: Uniform to prevent warping

Assembly Steps

Example: Hose Connector (15mm)

1. Design 3D model in CAD software
   📥 Download STEP file
2. Create two-part mold with parting line
3. 3D print mold in heat-resistant resin
4. Test fit with prototype injection

3.1 Planning & Preparation

Workshop Overview (2-3 hours)

Before the Day Checklist

• Choose space: room for presentation + outdoor area for demo
• Prepare slides (8-10 slides, image-heavy, in audience's language)
• Collect and clean plastic (HDPE/PP caps only)
• Test entire process: melting time, injection, cooling
• Build Kahoot quiz (8-12 questions from presentation)
• Make prizes in advance (keyrings, tokens from recycled plastic)
• Check all safety equipment

Team Roles

• Presenter — leads the talk, keeps energy up
• Demonstrator — operates machines, handles hot plastic (safety focus)
• Quiz Host — runs Kahoot, forms teams, keeps score
• Helper — welcomes people, manages group, assists with language

3.2 Activity 1: Introductory Presentation (20 min)

Key Topics to Cover

The Sun and Its Energy

• The Sun is about 109 times wider than Earth
• Surface temperature: ~5,500°C; core: ~15 million°C
• Sunlight takes 8 minutes to reach us

The Sun in History

• Divinity: worshipped as a god in many cultures
• Burning mirrors: legend of Syracuse — focused sunlight to burn Roman ships
• Sundial: clock using light and shadow

The Plastic Challenge

• Many types of plastic, each with different properties
• Each person ingests about 5 grams of microplastic per week
• In 2022, only 9.5% of plastic came from recycling

Sun Factory Project Solution

• Solar concentrator reaches up to 300°C
• Manual injection press pushes melted plastic into molds
• Result: new useful objects from waste plastic

3.3 Activity 2: Team Quiz Game (20 min)

Basketball Challenge + Kahoot

Turn assessment into a physical game! Before answering each question, teams throw plastic "waste" into a trash-can basket. Successful shot = team runs to answer.

Materials

• Trash can or basket
• Lightweight plastic pieces (bottle caps)
• Projector for Kahoot display
• One device for educator (controls answers)
• Recycled-plastic prizes for winners

Game Rules

1. Split into 3 teams of 3-4 people
2. Each team gets plastic pieces to throw
3. For each question: team scores basket → runs to educator → selects answer
4. Educator controls single device (keeps game fair)
5. Award recycled-plastic prizes to winners

Sample Quiz Questions

3.4 Activity 3: Live Demonstration (30-40 min)

Step-by-Step Process

Using the Cartridge — Detailed Steps

Extra Activity: Archimedes Mirror Boat

If time allows, demonstrate the legend! Build small boats with paper sails, use mirrors/lenses to concentrate sunlight and burn the sails — just like Archimedes allegedly did to Roman ships.

3.5 Facilitation Tips

Language Barrier

• Show, don't only tell: demonstration crosses language barriers
• Short sentences, one idea at a time
• Put key words on slides in audience's language
• Use images, not text walls — pictures need no translation

Keeping Energy High

• Change activity type often: talk → watch → play
• 20 minutes is max for sitting and listening
• Ask questions, invite predictions

If Something Goes Wrong

• Demo fails: show prepared objects, keep talking, take questions
• Internet fails: run quiz on paper or by show of hands
• Weather cloudy: show video of process, or use infrared lamp

Adaptations

3.6 Safety Guidelines

Safe Plastics Reference

Protective Equipment

• Heat-resistant gloves (300°C+)
• Safety glasses / UV protection
• Long sleeves, closed shoes, tied-back hair
• Fire extinguisher within reach
• First-aid kit nearby

Appendices & Resources

Team Articles (GitLab Knowledge Base)

• 📄 Emanuele Ceridono — Building a Replicable Custom Sun Concentrator
• 📄 Federico Guizzo — Building a Replicable Custom Manual Injector
• 📄 Maria Monica Cabarcas Granados — Producing Solar Plastic Recycled Goods (Molds)
• 📄 Sara Proietti — Capture and Spread Solar Knowledge Using AI
• 📄 Andrea Tessitore — Building a GAFAM-Free Community
• 📄 Marco Bernardo — Sun Factory History

3D Files & Documentation

• Solar Concentrator — STEP & GLTF files
• Manual Injector — STEP & GLTF files
• Cartridges — 3D Models
• Hose Connector Mold — 3D Models

External Resources

• Antenna Foundation Hub
• Instructables — Solar Plastic Injection